ارزیابی اثرات تغییر اقلیم بر میزان بارش در حوضه آبخیز بار نیشابور

Any long term and permanent change in average atmospheric conditions is known as climate change. Greenhouse gases emission are important variables in creating climate change. The global climate model or general circulation models (GCM) are among the instruments or methods for climate change studies. Precipitation as one of the most important climate parameters in water recourse management was chosen to be predicted under climate change scenarios in the Bar watershed, Neyshabour. In this study, the statistical downscaling model was used for downscaling the output of AOGCM model for the A1 scenario. The 1971-2000 period was used as the base period and the climate variable of interest was predicted for three periods of (2010-2039), (2040-2069) and (2070-2099). The results showed that the average annual rainfall in the three periods of  (2010-2039), (2040-2069) and (2070-2099) decreased 2/7, 5/2 and 6/3 percent, respectively. From 2010 toward 2099, rainfall in the months of October, November and December increases while it decreases in January and February.